1. Field of the Invention
This invention relates generally to the field of plastic vessels and specifically to a process for installing a fitting on such a vessel.
2. Description of the Related Art
Molded vessels have numerous applications for containing fluids. The vessels are made by any of several plastic forming processes, including rotational molding and blow molding. Many of the fluids are contained at high pressure. Therefore, the vessels are reinforced by filaments wound on the outer surface of the vessel, as described, for example, in U.S. Pat. Nos. 3,945,578 to Kaminsky and 5,012,950 to Knappe, both incorporated herein by reference.
Such vessels need one, and frequently several, ports for filling or emptying the vessel. The ports are commonly provided as a rigid fitting adapted to connect to a hose or pipe. Such fittings can be provided during the molding process. For example, a metal fitting can be held in the mold and the plastic molded around the fitting. This method, however, cannot be used to add a fitting after molding. Moreover, reconfiguring a mold is costly, thus, fittings cannot be located at different locations based on specified applications. U.S. Pat. No. 4,685,589 to Benton describes one way of installing a fitting after molding and before winding a vessel. An elastic seal is disposed between the fitting and the vessel.
Still, the need remains for a method of fabricating a fitting that allows the fitting to be located after molding of the vessel. The fitting should be firmly secured on the vessel and bonded therewith prior to winding.